This invention relates to switches and in particular to solid state switches. Heretofore, Hall Effect generators have been used primarily as keyswitches for keyboards and the like. Such keyswitches are manually depressed and released, resulting in rectilinear movement thereof. The movement of the keys changes the magnetic field to which a Hall Effect generator is exposed, thus causing a change in the generator output voltage.
One such keyboard is taught by Dalmasso (U.S. Pat. No. 3,611,358). Attached to and supported by each key stem is a magnet which moves with the key in rectilinear fashion relative to a stationary Hall Effect generator which senses a change in the intensity of the magnetic flux. A similar keyboard is described by Maupin et al (U.S. Pat. No. 3,596,114) in which keyswitch moves a magnet supported thereby in rectilinear fashion relative to a stationary Hall Effect generator.
Other related references are Turja (U.S. Pat. No. 3,449,517) which shows a Hall Effect generator moved relative to a stationary magnet, and Semmelman (U.S. Pat. No. 2,774,890) which shows the input and output terminals of a Hall Effect generator asymmetrically positioned.
In each of the above prior art keyboards, manual pressure must be maintained to hold the keyswitch in a depressed or actuated position, and when such pressure is removed, the switch returns to an "unactuated" position. These keyswitches are not suitable for use when it is desired that the switch remain in either position desired after manual pressure has been removed.
Heretofore, switches such as rocker action or slide switches have been mechanical in nature. An electrical circuit is completed by closure of mechanical contacts which, in turn, produce electrical "bounce" in the circuitry. This "bounce" must be eliminated if sensitive components are to be used elsewhere in the circuitry.
Another disadvantage of mechanical action switches is their limited life ratings (maximum 100,000 actuations). The complex mechanical design (typically 12 or more mechanical parts for rocker action switches) and contact resistance from oxide and nitride buildup are largely responsible for this limited lifetime. Furthermore, mechanical action switches must be connected to the electrical circuitry by soldering, wire wrap or other mechanical techniques.
It is therefore an object of the present invention to provide an improved solid state switch.
It is another object of the invention to provide a solid state switch which can remain activated without applying external force.
It is another object of the invention to provide an improved, more reliable, easier to assemble and longer lasting switch with fewer mechanical parts than prior mechanical action switches.
It is a further object of the invention to provide an improved switch that can be quickly and easily attached to a printed circuit board.